Halobutyl Rubber Definition: Halobutyl is a variety of synthetic rubber or elastomer and refers to halogenated butyl. The halobutyl rubber is the copolymer of isobutylene (98%) and a small amount of isoprene (2%). The abbreviation IIR is commonly used to describe butyl or halobutyl rubber as it stands for Isobutylene Isoprene rubber. The halobuty rubber is odorless and tasteless, though it may exhibit a slight characteristic odor. Comments The primary attributes of halobutyl rubber are excellent impermeability/air retention and good flex properties, resulting from low levels of unsaturation between long polyisobutylene segments. Tire innertubes were the first major use of halobutyl rubber, and this continues to be a significant market today. The quality of these tire innertubes is essential for the air retention and the lifespan of the tires by better resistance to heat, ozone and flex fatigue. Tire innerliners are by far the largest application for halobutyl rubber today. The halobutyl rubber provides higher curing rates and enabling co-vulcanization with general purpose rubbers such as natural rubber and styrene-butadiene rubber (SBR). The halobutyl rubber are available in two forms, the chlorinated (chlorobutyl) and brominated (bromobutyl). In addition to tire applications, the halobutyl rubbers are also used for vibration dampening, and stability, for pharmaceutical stoppers, construction sealants, hoses, and mechanical goods, because of their: - Good impermeability - Weathering resistance - Ozone resistance - High temperature resistance - Greater heat stability compared to other synthetic rubber - High damping properties - Wide latitude in cure and cocure with a variety of rubbers
Heads of Agreement Definition Heads of Agreement (HOA) refers to the first document signed between parties in the perspective to go for a fully bidding contract. Heads of Agreement may also be called Shake hands Agreement and is different from Memorandum of Understanding (MOU). Comments Parties willing to close a bidding agreement or contract are aware that such a process is complex and may take months. In some cases, it may also require the approval from relevant Authorities and legal publications. In the mean time the parties willing to start a cooperation need a foundation document. By Heads of Agreement, the document must be understood as to contains the Heads of all the articles to be detailed in the final contract. These Heads are also providing the parties with the guidelines to cooperate together. Therefore the Heads of Agreement materialize the link between the intentions of the parties to work on a common goal and the detailed content of all the articles proposed by the lawyers of both parties for the final bidding document. During the preparation of the final bidding document which may take a long period of time, there is always the risk that the representatives of the parties get more passionate by the points of disagreement than the common interest. Therefore the Heads of Agreement helps both parties to find the right balance between their mutual commitment in a common goals and the protection of their respective interests in the partnership. In that respect a Heads of Agreement will define the: - Object of the agreement - Parties\'s representatives - Roles and responsibilities of the parties - Legal entities supporting the process from the parties - Key milestones to reach the final bidding contracts - Key performances indicators of contract when signed - Regulation of reference to establish the final bidding contract Intentionally the Heads of Agreement is written without too much details as not bidding and to leave time to the representatives of the parties to come into the details and validate the feasibility of the contract in respect with their respective interests. The Heads of Agreement is different from a Memorandum of Understanding (MOU) in at least two aspects: - The Heads of Agreement is not bidding parties until the final contract is signed, while a Memorandum of Understanding may be bidding as a classical contract depending on the applicable regulations and its content - The Heads of Agreement reflects the intention of both parties to sign a formal bidding contract while the Memorandum of Understanding may be self sufficient without any contract to be signed behind. Precisely in some cases, the parties may prefer the Memorandum of Understanding because they do not intend to go through the whole formal process of a formal bidding contract even though the Memorandum of Understanding might have a legal value.
Heavy Crude Oil Definition: Heavy crude oil and extra heavy crude oil is any type of crude oil which does not flow easily. Physically heavy crude oil have higher viscosity and density or specific gravity with an heavier molecular composition Heavy crude oil has been defined as any liquid petroleum with an API gravity less than 20°. Extra Heavy crude oil have an API gravity below 10°. Comments: Heavy crude oil is closely related to natural bitumen from oil sands. Heavy crude oil and Extra heavy crude oil differ in the degree by which they have been degraded from the original crude oil by bacteria and erosion. Often, bitumen is present as a solid and does not flow at normal conditions, meaning sea level and 25°C ambient temperature. The largest reserves of heavy crude oil in the world are located north of the Orinoco river, in the so called Orinoco belt in Venezuela. These reserves are equivalent to the light crude oil reserves of Saudi Arabia. More than thirty countries are known to have heavy crude oil reserves. Production, transportation, and refining of heavy crude oil present special challenges compared to light crude oil. Generally, a diluent is added at regular distances in a pipeline carrying heavy crude to facilitate its flow.
Henry hub Definition: Henry hub is the pricing point for the natural gas future and spot contracts traded on the New York Mercantile Exchange (NYMEX). Physically the Henry hub is located in Erath, Louisiana, USA and belongs to the Sabine Pipeline LLC. Comments: Future and spot prices set at Henry hub are denominated in $/mbtu (million of British thermal units) and are generally seen to be the primary price set for the North American natural gas market. North American unregulated wellhead and burner-tip natural gas prices are closely correlated to those set at Henry Hub. The area surrounding the Henry hub was affected by the flooding and storm surge from hurricanes but the facility suffered minimal damage. In 2011, the Henry Hub was the site of a land dispute, in which Sabine, a subsidiary of Chevron, sued to condemn land near the site of the hub, and expropriate it from the Broussard family, who had owned it for generations, arguing that it was acting in the national interest. Natural gas is priced and traded at different locations throughout USA. These locations, referred to as market hubs, exist across the USA and are located at the intersection of major gas pipeline systems. There are over 30 major market hubs in the USA, the principle of which is known as the Henry Hub, located in Louisiana. The futures contracts that are traded on the NYMEX are Henry Hub contracts, meaning they reflect the price of natural gas for physical delivery at this hub. The price at which natural gas trades differs across the major hubs, depending on the supply and demand for natural gas at that particular point. The difference between the Henry Hub price and another hub is called the location differential. In addition to market hubs, other major pricing locations include citygates. Citygates are the locations at which distribution companies receive gas from a pipeline. Citygates at major metropolitan centers can offer another point at which natural gas is priced.
HVDC Definition: HVDC is the acronym of High Voltage Direct Current. HVDC refers to a technology to transmit high electric power across long distances, typically several hundreds kilometers Comments The modern form of HVDC transmission uses technology developed extensively in the 1930s in Sweden by ABB. Early commercial installations included one in Russia in 1951 between Moscow and Kashira, and a 10–20 MW system between Gotland and the mainland Sweden in 1954 The longest HVDC link in the world is currently the Xiangjiaba-Shanghai 2,071 km, 6400 MW link connecting the Xiangiiaba Dam to Shanghai in China. In 2012, the longest HVDC link will be the Rio Madeira link connecting the Amazonas to San Paulo area where the length of the DC line is over 2,500 km. The HVDC technology is used to transmit electricity over long distances by overhead transmission lines or submarine cables. It is also used to interconnect separate power systems, where traditional alternating current (AC) connections can not be used. In a high voltage direct current (HVDC) system, electric power is taken from one point in a three-phase AC network, converted to DC in a converter station, transmitted to the receiving point by an overhead line or cable and then converted back to AC in another converter station and injected into the receiving AC network. Typically, an HVDC transmission has a rated power of more than 100 MW and many are in the 1,000 - 3,000 MW range. HVDC transmissions are used for transmission of power over long or very long distances, because it then becomes economically attractive over conventional AC lines, since DC transmission can be done at no losses. The increased interest in recent years for transporting clean and renewable energy from remote hydro generation plants has also increased the interest in higher DC transmission voltage than presently used (i.e. 600 kV DC). This has led to development of Ultra High Voltage Direct Current (UHVDC) at 800 kV DC. In the lower range HVDC may also be used to transmit just a few tens of Megawatts (MW) power underground and under water, also over long distances. It offers numerous environmental benefits, including “invisible” power lines, neutral electromagnetic fields, oil-free cables and compact converter stations. HVDC increases the reliability of power grids, and the technology extends the economical power range of HVDC HVDC is quick to install and provides an alternative to conventional AC transmission systems and local generation. Possible applications include: - Connecting wind farms to power grids - Underground power links - Providing shore power supplies to islands and offshore oil & gas platform - Connecting asynchronous grids - City center infeed Overall the HVDC takes advantage on Conventional AC transmission as soon as either the power to transmit increases, either the distance increases, and of course when both increase because of the very low electrical losses left in the cable during the transmission. Even if some losses must be taken in the AC/DC and DC/AC power conversion stations, these losses with HVDC technology are negligible compared with the losses of the same power to be transmitted through conventional AC lines.